The present invention relates to a switch for selectively attaching desired computer peripherals to a desired computer and, in particular, to the case where one or more of the peripherals and/or computers requires a Universal Serial Bus connection.
It is often desirable to control multiple computers with a single keyboard/video/mouse (KVM) combination. It is also often desirable to be able to control a single computer from one of several KVM combinations or to be able to select from both multiple KVM combinations and multiple computers. Many KVM switches that handle conventional keyboards and mice have been made and sold.
Universal Serial Bus (USB) is a peripheral bus standard developed by the PC and telecom industry, including Compaq, DEC, IBM, Intel, Microsoft, NEC and Northern Telecom. USB defines a bus and protocols for the connection of computer peripherals to computers (and to each other). "Universal Serial Bus Specification", Compaq, Intel, Microsoft, NEC, Revision 1.1, Sep. 23, 1998, describes USB and its implementation and is incorporated herein by reference. Proposed and actual USB devices include keyboards, mice, telephones, digital cameras, modems, digital joysticks, CD-ROM drives, tape and floppy drives, digital scanners, printers, MPEG-2 video-base products, and data digitizers and other relatively low bandwidth devices. USB supports data rates of up to 12 Mbits/sec.
Present KVM switches are designed to connect conventional keyboards and mice to conventional keyboard and mouse input ports of computers. The advent of USB presents an obstacle for present KVM switches. For example, it is desirable to be able to connect a non-USB mouse and keyboard to any one of a group of both USB and non-USB computers using a KVM switch or to connect any one of a group of both USB and non-USB keyboard and mouse combinations to a single USB computer. As a further example, it may be desirable to switchably connect other USB or non-USB peripherals to USB or non-USB computers. Present KVM switches cannot switchably select USB devices, much less connect USB to non-USB devices.